Surgical stapling device

ABSTRACT

A surgical stapling device includes a tool assembly that has a staple cartridge that includes a perfluorocarbon (hereinafter “PFC”) solution that is injected into tissue when the surgical stapling device is fired to improve oxygenation of tissue being treated. In aspects of the disclosure, the tool assembly of the surgical stapling device includes a staple cartridge that has staples that are supported on pushers and an actuation sled that is movable through the staple cartridge into engagement with the pushers to eject staples from the staple cartridge. In certain aspects of the disclosure, the PFC solution is contained within the pushers of a staple cartridge of the tool assembly and the actuation sled includes protrusions that engage the pushers to eject the PFC solution from the pushers when the stapling device is fired.

FIELD

This disclosure is directed to surgical stapling devices and, more particularly, to surgical stapling devices that have a tool assembly including a reservoir having a perfluorocarbon solution for injecting into stapled tissue.

BACKGROUND

Surgical stapling devices for ejecting staples to join tissue or tissue segments in a fast and efficient manner in a variety of surgical procedures, e.g., anastomoses procedures, are well known. Typically, a surgical stapling device includes a tool assembly having first and second jaws that support a cartridge assembly and an anvil, respectively. The cartridge assembly includes a staple cartridge that supports a plurality of staples. The first and second jaws are mounted together to allow for movement of the tool assembly between open and clamped positions.

During a variety of different types of surgical procedures for dissecting a vessel or joining two vessel sections, the tissue forming the vessel or vessel sections is/are clamped between the anvil and the cartridge assembly. Subsequently, the vessel or vessel sections is/are cut with a knife and sutured with staples that are ejected from the cartridge assembly through tissue of the vessel and/or vessel sections and formed by the anvil. If there is not adequate oxygenation of tissue in the area of the formed staples, the tissue will necrose and leakage may occur. Leakage may result in several post-operative complications including sepsis and death.

Accordingly, a continuing need exists in the suturing arts for a surgical stapling device that can improve oxygenation of tissue in the area of the anastomosis.

SUMMARY

Aspects of this disclosure are directed to a surgical stapling device that includes a tool assembly that has a staple cartridge that includes a perfluorocarbon (hereinafter “PFC”) solution that is injected into tissue when the surgical stapling device is fired to improve oxygenation of tissue being treated.

One aspect of the disclosure is directed to a tool assembly an anvil and a cartridge assembly. The cartridge assembly is coupled to the anvil such that the tool assembly is movable between open and clamped positions. The cartridge assembly includes a channel member and a staple cartridge. The channel member defines a cavity and a staple cartridge that is received within the cavity. The staple cartridge includes a cartridge body, a plurality of staples, at least one pusher, and a PFC solution. The cartridge body defines staple receiving pockets. The plurality of staples is received within the staple receiving pockets. Each of the plurality of staples has a back span and a leg extending from each of the back span. The at least one pusher includes a body defining a reservoir. The body has a staple supporting surface and supports at least one needle. The at least one needle has a first end that communicates with the reservoir and a second end that projects above the staple supporting surface and extends towards the anvil. The PFC solution is received within the reservoir.

In aspects of the disclosure, the tool assembly includes an actuation sled having a ramp and is movable through the cartridge body into engagement with the at least one pusher to advance the plurality of staples from the staple receiving pockets into the anvil.

In some aspects of the disclosure, the actuation sled includes protrusions that engage the body of the pusher to force the PFC solution from the reservoir through the at least one needle.

In certain aspects of the disclosure, the at least one needle includes at least one nanoneedle.

In aspects of the disclosure, the at least one nanoneedle includes a plurality of nanoneedles.

In some aspects of the disclosure, each of the plurality of nanoneedles has a length and the back span of each of the plurality of staples has a diameter, and the length of each of the plurality of nanoneedles is greater than the diameter of the back span of each of the plurality of staples.

In certain aspects of the disclosure, the cartridge body defines a central knife slot and the staple receiving pockets are aligned in rows on each side of the central knife slot.

In aspects of the disclosure, the pusher includes a plurality of pushers and the actuation sled is positioned to sequentially engage the plurality of pushers.

In some aspects of the disclosure, the staple supporting surface of the pusher defines a cylindrical concavity that receives the back span of each of the plurality of staples.

Another aspect of the disclosure is directed to a tool assembly including an anvil and a cartridge assembly. The cartridge assembly is coupled to the anvil such that the tool assembly is movable between open and clamped positions. The cartridge assembly includes a channel member defining a cavity and a staple cartridge. The staple cartridge is received within the cavity of the channel member and includes a cartridge body, a plurality of staples, at least one pusher, and a reservoir including a PFC solution. The cartridge body defines staple receiving pockets and the plurality of staples is received within the staple receiving pockets. Each of the plurality of staples has a back span and a leg extending from respective ends of the back span. The at least one pusher includes a body having at least one staple supporting surface that supports the back spans of the plurality of staples.

Another aspect of the disclosure is directed to a pusher for a surgical stapling device that includes, a body defining a reservoir that has a staple supporting surface and supports at least one needle. The at least one needle has a first end communicating with the reservoir and a second end projecting above the staple supporting surface of the body. A PFC solution is received within the reservoir.

In aspects of the disclosure, the at least one needle includes a plurality of nanoneedles.

Other aspects of the disclosure will be appreciated from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of the disclosed stapling device are described herein below with reference to the drawings, wherein:

FIG. 1 is a side perspective view of a surgical stapling device including aspects of the disclosure with a tool assembly of the stapling device in an open position;

FIG. 2 is an enlarged view of the indicated area of detail shown in FIG. 1;

FIG. 3 is an exploded view of the cartridge assembly shown in FIG. 2;

FIG. 4 is an enlarged view of the indicated area of detail shown in FIG. 3 illustrating a distal portion of a drive assembly of the surgical stapling device;

FIG. 5 is perspective view from a proximal end of the distal portion of the drive assembly shown in FIG. 4;

FIG. 6 is a side perspective view of staples and pushers of a staple cartridge of the cartridge assembly shown in FIG. 3 with parts separated;

FIG. 7 is an enlarged view of the staples and pushers shown in FIG. 6 with the staples supported on the pushers;

FIG. 8 is a cross-sectional view taken along section line 8-8 of FIG. 6;

FIG. 9 is a side perspective view of the tool assembly of the surgical stapling device shown in FIG. 1 with the tool assembly in the clamped position about tissue;

FIG. 10 is a cross-sectional view taken along section line 10-10 of FIG. 9;

FIG. 11 is a cross-sectional view taken through the tool assembly shown in FIG. 9 with the tool assembly in a fired position;

FIG. 12 is an enlarged view of the indicated area of detail shown in FIG. 11; and

FIG. 13 is a cross-sectional view taken along section line 13-13 of FIG. 12.

DETAILED DESCRIPTION

The disclosed surgical stapling device will now be described in detail with reference to the drawings in which like reference numerals designate identical or corresponding elements in each of the several views. However, it is to be understood that the disclosed aspects are merely exemplary of the disclosure and may be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the disclosure in virtually any appropriately detailed structure.

In this description, the term “proximal” is used generally to refer to that portion of the device that is closer to a clinician, while the term “distal” is used generally to refer to that portion of the device that is farther from the clinician. In addition, the term “endoscopic” is used generally used to refer to endoscopic, laparoscopic, arthroscopic, and/or any other procedure conducted through a small diameter incision or cannula. Further, the term “clinician” is used generally to refer to medical personnel including doctors, nurses, and support personnel. Moreover, directional terms such as front, rear, upper, lower, top, bottom, and similar terms are used to assist in understanding the description and are not intended to limit the disclosure.

The disclosed surgical stapling device includes a tool assembly that has a staple cartridge that includes a perfluorocarbon (hereinafter “PFC”) solution that is injected into tissue when the surgical stapling device is fired to improve oxygenation of tissue being treated. In aspects of the disclosure, the tool assembly of the surgical stapling device includes a staple cartridge that has staples that are supported on pushers and an actuation sled that is movable through the staple cartridge into engagement with the pushers to eject staples from the staple cartridge. In certain aspects of the disclosure, the PFC solution is contained within the pushers of the staple cartridge of the tool assembly and the actuation sled includes protrusions that engage the pushers to eject the PFC solution from the pushers when the stapling device is fired.

FIG. 1 illustrates a surgical stapling device shown generally as stapling device 10 that includes a handle assembly 12, an elongate body or adapter assembly 14, and a tool assembly 16. As illustrated, the handle assembly 12 is powered and includes a stationary handgrip 18 and actuation buttons 20. The actuation buttons 20 are operable to actuate various functions of the tool assembly 16 via the adapter assembly 14 including approximation, stapling, and cutting. In certain aspects of the disclosure, the handle assembly 12 supports batteries (not shown) that provide power to the handle assembly 12 to operate the stapling device 10. Although the stapling device 10 is illustrated as a powered stapling device, it is envisioned that the disclosed tool assembly 16 is suitable for use with manually powered surgical stapling devices as well as robotically controlled stapling devices.

The adapter assembly 14 includes a proximal portion 14 a and a distal portion 14 b. The proximal portion 14 a is coupled to the handle assembly 12 and the distal portion 14 b supports the tool assembly 16. In aspects of the disclosure, the tool assembly 16 forms part of a reload assembly 21 that is removably supported on the distal portion 14 b of the adapter assembly 14 and can be replaced after the stapling device 10 is fired to facilitate reuse of the stapling device 10. It is also envisioned that the tool assembly 16 can be fixedly coupled directly to the distal portion 14 b of the adapter assembly 14.

The tool assembly 16 of the stapling device 10 includes a cartridge assembly 30 and an anvil 32. The cartridge assembly 30 and the anvil 32 are coupled together such that the tool assembly 16 can pivot between an open position (FIG. 1) and a clamped position (FIG. 9). In the clamped position, the anvil 32 and the cartridge assembly 30 are in juxtaposed alignment with each other.

FIGS. 2 and 3 illustrate the cartridge assembly 30 which includes a channel member 34, and a staple cartridge 40. The channel member 34 includes side walls 36 and a bottom wall 38 that define a cavity 34 a (FIG. 3) that receives the staple cartridge 40. In aspects of the disclosure, the staple cartridge 40 is removably received within the cavity 34 a of the channel member 34 to allow for replacement of the staple cartridge 40 after each firing of the stapling device 10 to facilitate reuse of the stapling device 10 (FIG. 1).

FIG. 3 illustrates an exploded view of the staple cartridge 40 which includes a cartridge body 42, staples 44, pushers 46, and a staple guard (not shown). The staple guard (not shown) is secured to the cartridge body 42 to retain the staples 44 and pushers 46 within the cartridge body as known in the art and is not described The cartridge body 42 of the staple cartridge 40 is received within the cavity 34 a defined by the channel member 34 and includes a tissue engaging surface 52. The cartridge body 42 defines a central knife slot 54 and a plurality of staple receiving pockets 56 that are arranged in rows on each side of the central knife slot 54. In certain aspects of the disclosure, the tissue engaging surface 52 of the staple cartridge 40 has a stepped configuration with a raised surface adjacent the central knife slot 54 and lower surfaces positioned outwardly of the knife slot 54 towards the side walls 36 of the channel member 34. Alternatively, the tissue engaging surface 52 can be planar. Each of the staple receiving pockets 56 receives a staple 44 (FIG. 3) and a pusher 46. In some aspects of the disclosure, the staples 44 in the different rows of staple receiving pockets 56 vary in length. Alternately, the staples 44 can be uniformly sized in all or some of the rows of the staple receiving pockets 56. Although three rows of staple receiving pockets 56 are illustrated, it is envisioned that the cartridge body 42 can include one or more rows of staple receiving pockets 56, e.g., two, four, etc.

The tool assembly 16 also includes a drive assembly 60 which includes a coupling member 62, a flexible drive beam 64, and a working end 66. The drive beam 64 of the drive assembly 60 has a proximal portion 64 a and a distal portion 64 b. The proximal portion 64 a of the drive beam 64 supports the coupling member 62 and the distal potion 64 b of the drive beam 64 supports the working end 66 of the drive assembly 60. The coupling member 62 of the drive assembly 60 is adapted to be coupled to a control rod (not shown) of the adapter assembly 14 (FIG. 1) such that longitudinal movement of the control rod (not shown) within the adapter assembly 14 (FIG. 1) causes longitudinal movement of the drive assembly 60 in relation to the cartridge assembly 30 and the anvil 32 between retracted and advanced positions. U.S. Pat. No. 6,241,139 (hereinafter “the '139 Patent”) discloses a stapling device and describes the interconnection between a drive assembly and control rod suitable for use herein in detail.

The working end 66 of the drive assembly 60 includes a clamping member 70. In aspects of the disclosure, the clamping member 70 has an I-Beam configuration and includes a first beam 74, a second beam 76, and a vertical strut 78 that interconnects the first beam 74 and the second beam 76. The first beam 74 is engaged with the anvil 32 and the second beam 76 is engaged with the cartridge assembly 30 such that movement of the working member 66 from the retracted position to the advanced position in relation to the cartridge assembly 30 and the anvil 32 moves the tool assembly 16 from its open position to its clamped position to define a maximum tissue gap between the cartridge assembly 30 and the anvil 32. In aspects of the disclosure, the vertical strut 78 of the working end 66 of the drive assembly 60 includes or supports a knife blade 80. The '139 Patent describes operation of the working end of a suitable drive assembly in further detail.

The tool assembly 16 of the stapling device 10 includes an actuation sled 82 that is engaged with the distal portion of the drive beam 64 of the drive assembly 60 and is received within the cartridge body 42. In aspects of the disclosure, the actuation sled 82 is fixedly secured to the working end 66 of the drive assembly 60 such that movement of the drive assembly 64 between its retracted and advanced positions causes movement of the actuation sled 82 within the cartridge assembly 30 between retracted and advanced positions. Alternately, the actuation sled 82 can be in abutting relation to the working end 66 of the drive assembly 60 such that movement of the drive assembly between its retracted and advanced positions causes movement of the actuation sled 82 to its advanced position but does not retract the actuation sled 82 from its advanced position.

When the drive assembly 60 is moved from its retracted position to its advanced position, the actuation sled 82 is moved from its retracted position to its advanced position. As the actuation sled 82 moves towards its advanced position, the actuation sled 82 moves into sequential engagement with the pushers 46 to urge the pushers 46 upwardly as viewed in FIG. 3 to eject the staples 44 from the staple receiving pockets 56 of the cartridge body 42. The '139 Patent describes engagement between the actuation sled 82 and the pushers 46 in detail.

FIGS. 4 and 5 illustrate the distal portion 64 b of the drive assembly 60 and the actuation sled 82 in further detail. In aspects of the disclosure, the actuation sled 82 includes spaced ramps 90 that are positioned to engage the pushers 46 as the actuation sled 82 is moved through the staple cartridge 40 to move or lift the pushers 46 within the cartridge body 42 of the staple cartridge 40 when the stapling device 10 (FIG. 1) is fired. The spaced ramps 90 define channels 92 that receive the pushers 46 when the actuation sled 82 moves from its retracted position to its advanced position. Each of the spaced ramps 90 includes one or more protrusions 94 that extend transversely from an upper end of the spaced ramps 90 into the channels 92. The actuation sled 82 also includes a central guide member 96 that centrally locates the actuation sled 82 within the cartridge body 42 as the actuation sled 82 moves longitudinally within the cartridge body 42 of the staple cartridge 40. The central guide member 96 also includes protrusions 94 that extend into the channels 92 through which the pushers 46 move to eject the staples 44 from the cartridge body 42.

FIGS. 6-8 illustrate the staples 44 and the pushers 46 in further detail. Each of the pushers 46 includes a body 100 that includes a staple supporting surface 102 and tubular needles 104 that project from the body 100 towards the tissue engaging surface 52 of the cartridge body 42. In aspects of the disclosure, the needles 104 are in the form of nanoneedles or microneedles. Nanoneedles are small scale devices that overcome resistance during drug diffusion by creating conduits of small dimension through bio membranes. The needles 104 extend through the body 42 of the pushers 46 and communicate with a reservoir 106 that is defined by the body 100 of the respective pusher 46. The reservoir 106 is filled with PFC solution 108.

Each of the staples 44 includes a back span 110 and legs 112 that extend from each end of the of the back span 110. Each of the legs 112 includes a tapered tip 112 a for piercing tissue “T” (FIG. 9). The back span 110 of each of the staples 44 is supported on the staple supporting surface 102 of a respective pusher 46. In aspects of the disclosure, the back span 110 of each of the staples 44 is cylindrical and the staple supporting surface 102 of each of the pushers 44 defines a cylindrical concavity. Alternately, other configurations are envisioned. In some aspects of the disclosure, when the back spans 110 of the staples 44 are received on the staple supporting surfaces 102 of the pushers 46, the needles 104 have a height that is greater than the diameter of the back spans 110 and extend above the back spans 110 as viewed in FIG. 7.

As illustrated, the pushers 46 are coupled together with cam members 120. Each of the cam members 120 includes a tapered bottom surface 120 a as viewed in FIG. 6 that is aligned with one of the spaced ramps 90 (FIG. 5) of the actuation sled 82 when the staple cartridge 40 is assembled. As such, the pushers 44 are aligned with the channels 92 of the actuation sled 82. Although it is illustrated that three pushers 44 are coupled together with two cam members 120 and move in unison, it is envisioned that the pushers 44 need not be coupled to each other, and that any number of pushers 46 can be coupled together and move in unison, e.g., two, three, four, etc.

FIGS. 9-13 illustrate the tool assembly 16 with the tool assembly 16 clamped about tissue “T”. FIGS. 9 and 10 illustrate the tool assembly 16 in a clamped position about tissue prior to firing the stapling device 10 (FIG. 1). In this position, the pushers 46 have not been engaged by the actuation sled 82 (FIG. 3) and are in their lowest or retracted position within the cartridge body 42 of the staple cartridge 40. As illustrated, the staples 44 are recessed within the staple receiving pockets 56 (FIG. 3) of the cartridge body 42 beneath the tissue “T” and the needles 104 extend towards the anvil 32 to a position above the back span 110.

FIGS. 11-13 illustrate the tool assembly 16 as the stapling device 10 (FIG. 1) is fired. When the stapling device 10 (FIG. 1) is fired, the actuation sled 82 is moved through the cartridge body 42 of the staple cartridge 40 in response to movement of the drive assembly 60 from its retracted position to its advanced position. As the actuation sled 82 is advanced within the cartridge body 42, the ramps 90 (FIG. 4) of the actuation sled 82 sequentially engage the cam members 120 (FIG. 11) of the pushers 46 to lift the pushers 46 within the staple receiving pockets 56 (FIG. 3) of the cartridge body 42 of the staple cartridge 40 in the direction of arrows “A” in FIG. 11 to eject the staples 44 from the staple receiving pockets 56 into the anvil 32 (FIG. 11). Because the height of the needles 104 is greater than the diameter of the back span 110 of the staples 44, the needles 104 pierce the tissue “T” as the staples 44 are formed against the anvil 32. As the actuation sled 82 passes by the pushers 46, the protrusions 94 (FIG. 5) on the upper ends of the ramps 90 and central guide member 96 of the actuation sled 82 (which extend laterally into the channels 92 defined between the spaced ramps 90 of the actuation sled 82) engage side walls of the body 100 of the pushers 46. Engagement of the protrusions 94 with the side walls of the body 100 of the pushers 46 forces the PFC solution 108 from the reservoir 106 through the needles 104 into the tissue “T” adjacent a staple line formed by the rows of staples 44 (FIG. 13). It is noted that where the actuation sled 82 is fixedly coupled to the working end 66 of the drive assembly 60, the protrusions on the actuation sled 82 will engage each of the pushers 46 a second time to force more PFC solution 108 from the reservoir 106 through the needles 104 into the tissue “T” as the actuation sled 82 is returned from its advanced position to its retracted position.

When the PFC solution 108 is injected into the tissue, the PFC solution 108 delivers oxygen to ischemic regions of the staple line that may have been compromised during the surgical procedure to minimize any likelihood of tissue necrosis. The delivery of the PFC solution is particularly beneficial in surgical procedures where there is a limited amount of tissue for stapling.

Although this disclosure illustrates the use of PFC solution in a linear type stapler, it is envisioned that the use of PFC could be incorporated into any stapling device for stapling tissue including circular stapling devices. In a circular stapling device, there may only be a single pusher and the protrusions could be formed on a stationary portion of a shell assembly of the circular stapling device. It is also envisioned that the reservoir for storing the PFC solution need not be in the pushers but could be in any portion of the cartridge assembly including the cartridge body. Further, although the PFC solution is disclosed as being delivered via interaction of the actuation sled and the pushers, it is envisioned that the PFC solution could be delivered via a number of different devices that function in response to firing of the stapling device or independently thereof.

Persons skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are non-limiting exemplary aspects of the disclosure. It is envisioned that the elements and features illustrated or described in connection with one exemplary aspects of the disclosure may be combined with the elements and features of another without departing from the scope of the disclosure. As well, one skilled in the art will appreciate further features and advantages of the disclosure based on the above-described aspects of the disclosure. Accordingly, the disclosure is not to be limited by what has been particularly shown and described, except as indicated by the appended claims. 

What is claimed is:
 1. A tool assembly comprising: an anvil; and a cartridge assembly coupled to the anvil such that the tool assembly is movable between open and clamped positions, the cartridge assembly including a channel member defining a cavity and a staple cartridge, the staple cartridge received within the cavity of the channel member and including: a cartridge body defining staple receiving pockets; a plurality of staples received within the staple receiving pockets, each staple of the plurality of staples having a back span and a leg extending from each end of the back span; at least one pusher including a body defining a reservoir, the body having a staple supporting surface and supporting at least one needle, the at least one needle having a first end communicating with the reservoir and a second end projecting above the staple supporting surface and extending towards the anvil; and a PFC solution received within the reservoir.
 2. The tool assembly of claim 1, further including an actuation sled having a ramp, the actuation sled being movable through the cartridge body into engagement with the at least one pusher to advance the plurality of staples from the staple receiving pockets into the anvil.
 3. The tool assembly of claim 2, wherein the actuation sled includes protrusions that engage the body of the pusher to force the PFC solution from the reservoir through the at least one needle.
 4. The tool assembly of claim 3, wherein the at least one needle includes at least one nanoneedle.
 5. The tool assembly of claim 4, wherein the at least one nanoneedle includes a plurality of nanoneedles.
 6. The tool assembly of claim 5, wherein each nanoneedle of the plurality of nanoneedles has a length and the back span of each staple of the plurality of staples has a diameter, the length of each nanoneedle of the plurality of nanoneedles being greater than the diameter of the back span of each staple of the plurality of staples.
 7. The tool assembly of claim 2, wherein the pusher includes a plurality of pushers and the actuation sled is positioned to sequentially engage the plurality of pushers.
 8. The tool assembly of claim 1, wherein the cartridge body defines a central knife slot and the staple receiving pockets are aligned in rows on each side of the central knife slot.
 9. The tool assembly of claim 1, wherein the staple supporting surface of the pusher defines a cylindrical concavity that receives the back span of each staple of the plurality of staples.
 10. A tool assembly comprising: an anvil; and a cartridge assembly coupled to the anvil such that the tool assembly is movable between open and clamped positions, the cartridge assembly including a channel member defining a cavity and a staple cartridge, the staple cartridge received within the cavity of the channel member and including: a cartridge body defining staple receiving pockets; a plurality of staples received within the staple receiving pockets, each staple of the plurality of staples having a back span and a leg extending from respective ends of the back span; at least one pusher including a body having at least one staple supporting surface, the at least one staple supporting surface supporting the back spans of the plurality of staples; and a reservoir including a PFC solution.
 11. The tool assembly of claim 10, further including an actuation sled having a ramp, the actuation sled being movable through the cartridge body into engagement with the at least one pusher to advance the plurality of staples from the staple receiving pockets into the anvil.
 12. The tool assembly of claim 10, wherein the reservoir is defined within the at least one pusher and the actuation sled includes protrusions that engage the body of the pusher to force the PFC solution from the reservoir.
 13. The tool assembly of claim 12, wherein the at least one pusher supports at least one needle, the at least one needle having a first end communicating with the reservoir and a second end projecting above the staple supporting surface and extending towards the anvil.
 14. The tool assembly of claim 13, wherein the at least one needle includes a plurality of nanoneedles.
 15. The tool assembly of claim 14, wherein each nanoneedle of the plurality of nanoneedles has a length and the back span of each staple of the plurality of staples has a diameter, the length of each nanoneedle of the plurality of nanoneedles being greater than the diameter of the back span of each staple of the plurality of staples.
 16. The tool assembly of claim 12, wherein the at least one pusher includes a plurality of pushers and the actuation sled is positioned to sequentially engage the plurality of pushers.
 17. The tool assembly of claim 10, wherein the cartridge body defines a central knife slot and the staple receiving pockets are aligned in rows on each side of the central knife slot.
 18. The tool assembly of claim 10, wherein the staple supporting surface of the at least one pusher defines at least one cylindrical concavity that receives the back span of each staple of the plurality of staples.
 19. A pusher for a surgical stapling device comprising: a body defining a reservoir, the body having a staple supporting surface and supporting at least one needle, the at least one needle having a first end communicating with the reservoir and a second end projecting above the staple supporting surface of the body, and a PFC solution received within the reservoir.
 20. The pusher of claim 19, wherein the at least one needle includes a plurality of nanoneedles. 